Sigma 24-70mm 2.8 anyone?

Since there are no fast zooms for FF e-mount yet I was thinking about getting this inexpensive Sigma 24-70mm 2.8 to use with my A7 with the LA-EA4.
Has anyone tried it? I´m curious regarding optical performance wide open in low light and AF speed.

Around the same price range I can find a minolta 28-70mm 2.8, which is supposed to be better...but I´d really like to have the 24mm at wide end.